As children transition from elementary to middle school, there are changes to their social context that include exposure to unfamiliar age mates and reorganization of existing peer groups which generate a number of challenges to be met. Some children negotiate these changes and new challenges easily, while others have greater difficulty. A child's temperament may influence their success or failure in this process. Behavioral Inhibited children may be particularly vulnerable to problems in social adaptation across the middle school years and into adolescence. Behavioral Inhibition is a temperament, identified early in childhood that involves heightened sensitivity to novelty, withdrawal from mildly stressful and unfamiliar events, and social reticence. We have recruited a large cohort (n=315) of infants and have carefully characterized their temperamental disposition to behavioral inhibition over the period of infancy and early childhood. We now wish to see these children before they enter middle school (10-11 years of age) and then soon after they transition to early adolescence (12-13 years of age). We will observe their social competence with familiar and unfamiliar peers and assess their attention bias to threat, as well as cognitive self-monitoring, in order to gain a detailed understanding of the social and cognitive mechanisms that influence the pathways from temperament to adaptive or maladaptive outcomes during this important period of development. Our unique and innovative approach involves behavioral observation of dyadic social interaction with familiar and unfamiliar peers when children are 10-11 years of age, assessment of cognitive factors at that age, as well as questionnaire measures of biological factors and school context. We will use these data to predict social competence in a peer group as well as incidence of psychopathology at age 12-13. This approach will allow us to identify how specific social and cognitive mechanisms moderate initial child temperament of behavioral inhibition to increase or diminish the risk for poor social adaptation and heightened incidence of psychopathology.